Terraform AWS API Gateway Lambda Integration

A Terraform module for integrating a lambda to an existing API Gateway REST API in AWS.

The API Gateway Lambda integration requires:

• An existing API Gateway REST API
• An existing Lambda function

The API Gateway Lambda integration consists of:

• resources
• methods
• integrations
• permissions

Usage

To use the module, include something like the following in your Terraform configuration:

module "api_gateway_lambda_integration" {
  source  = "infrablocks/api-gateway-lambda-integration/aws"
  version = "2.0.0"

  region = "eu-west-2"

  component             = "lambda-resource"
  deployment_identifier = "production"

  api_gateway_rest_api_id               = "x3H41ka22w"
  api_gateway_rest_api_root_resource_id = "321pyrfif2"

  lambda_function_name = "lambda-function"
}

By default, the resource will allow any method at any path. However, stricter path definitions can be provided using the api_gateway_resource_definitions variable.

See the Terraform registry entry for more details.

Inputs

Name	Description	Default	Required
region	The region into which to deploy the API Gateway Lambda integration.	-	Yes
component	The component for which the API Gateway Lambda integration is being managed.	-	Yes
deployment_identifier	An identifier for this instantiation.	-	Yes
lambda_function_name	The name of the Lambda function to integrate from the API Gateway REST API.	-	Yes
api_gateway_rest_api_id	The ID of the API Gateway REST API for which this Lambda integration is being managed.	-	Yes
api_gateway_rest_api_root_resource_id	The ID of the API Gateway REST API's root resource.	-	Yes
api_gateway_resource_definitions	Definitions of the resources to manage on the API Gateway REST API for the Lambda.	[ { path: "{proxy+}", method: "ANY" } ]	No
use_proxy_integration	Whether to use a proxy integration (true, "AWS_PROXY") or a custom integration (false, "AWS").	true	No
tags	A map of tags to add to created infrastructure components.	{}	No
timeout_milliseconds	Custom timeout. The default value is 29,000 milliseconds.	-	No

Outputs

Name	Description
api_gateway_redeployment_triggers	A map of data which upon change should trigger a redeployment of the stage.

Compatibility

This module is compatible with Terraform versions greater than or equal to Terraform 1.3 and the Terraform AWS provider 4.0.

Development

Machine Requirements

In order for the build to run correctly, a few tools will need to be installed on your development machine:

• Ruby (3.1)
• Bundler
• git
• git-crypt
• gnupg
• direnv
• aws-vault

Mac OS X Setup

Installing the required tools is best managed by homebrew.

To install homebrew:

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

Then, to install the required tools:

# ruby
brew install rbenv
brew install ruby-build
echo 'eval "$(rbenv init - bash)"' >> ~/.bash_profile
echo 'eval "$(rbenv init - zsh)"' >> ~/.zshrc
eval "$(rbenv init -)"
rbenv install 3.1.1
rbenv rehash
rbenv local 3.1.1
gem install bundler

# git, git-crypt, gnupg
brew install git
brew install git-crypt
brew install gnupg

# aws-vault
brew cask install

# direnv
brew install direnv
echo "$(direnv hook bash)" >> ~/.bash_profile
echo "$(direnv hook zsh)" >> ~/.zshrc
eval "$(direnv hook $SHELL)"

direnv allow <repository-directory>

Running the build

Running the build requires an AWS account and AWS credentials. You are free to configure credentials however you like as long as an access key ID and secret access key are available. These instructions utilise aws-vault which makes credential management easy and secure.

To run the full build, including unit and integration tests, execute:

aws-vault exec <profile> -- ./go

To run the unit tests, execute:

aws-vault exec <profile> -- ./go test:unit

To run the integration tests, execute:

aws-vault exec <profile> -- ./go test:integration

To provision the module prerequisites:

aws-vault exec <profile> -- ./go deployment:prerequisites:provision[<deployment_identifier>]

To provision the module contents:

aws-vault exec <profile> -- ./go deployment:root:provision[<deployment_identifier>]

To destroy the module contents:

aws-vault exec <profile> -- ./go deployment:root:destroy[<deployment_identifier>]

To destroy the module prerequisites:

aws-vault exec <profile> -- ./go deployment:prerequisites:destroy[<deployment_identifier>]

Configuration parameters can be overridden via environment variables. For example, to run the unit tests with a seed of "testing", execute:

SEED=testing aws-vault exec <profile> -- ./go test:unit

When a seed is provided via an environment variable, infrastructure will not be destroyed at the end of test execution. This can be useful during development to avoid lengthy provision and destroy cycles.

To subsequently destroy unit test infrastructure for a given seed:

FORCE_DESTROY=yes SEED=testing aws-vault exec <profile> -- ./go test:unit

Common Tasks

Generating an SSH key pair

To generate an SSH key pair:

ssh-keygen -m PEM -t rsa -b 4096 -C integration-test@example.com -N '' -f config/secrets/keys/bastion/ssh

Generating a self-signed certificate

To generate a self signed certificate:

openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem -days 365

To decrypt the resulting key:

openssl rsa -in key.pem -out ssl.key

Managing CircleCI keys

To encrypt a GPG key for use by CircleCI:

openssl aes-256-cbc \
  -e \
  -md sha1 \
  -in ./config/secrets/ci/gpg.private \
  -out ./.circleci/gpg.private.enc \
  -k "<passphrase>"

To check decryption is working correctly:

openssl aes-256-cbc \
  -d \
  -md sha1 \
  -in ./.circleci/gpg.private.enc \
  -k "<passphrase>"

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/infrablocks/terraform-aws-api-gateway-lambda-resource. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The library is available as open source under the terms of the MIT License.